Set up basic analytics for Elasticsearch

Done when

• We've decided what data to collect
• We're collecting it

Some metrics that might be meaningful to capture:

• Percent of users who click a result after searching
• If they click a result, which page of results was it on/where was it ranked

Implementation notes

• https://www.elastic.co/docs/current/search-ui/api/core/plugins/analytics-plugin
• https://www.elastic.co/guide/en/elasticsearch/reference/8.15/behavioral-analytics-overview.html